1. Field of the Invention
The invention relates to a pump apparatus for a free-flowing, in particular pasty and/or liquid, product and a dispenser having such a pump apparatus. The pump apparatus and the dispenser are intended in particular for pumping or storing and dispensing a product for personal hygiene and/or cleaning, for example for skin care. The product may be, for example, pasty and consist of a paste or cream. The product can, however, also consist of a liquid, for example a liquid sunscreen agent or a liquid soap, all intermediate states between pasty and liquid being possible.
Many free-flowing cosmetic products intended for personal hygiene, in particular skin care, tend to undergo undesired changes under the action of air and/or light. For example, such products may contain active ingredients and/or auxiliaries and/or fragrance materials, such as, for example, sunscreen substances or essential oils, which may oxidize under the action of the oxygen present in the air and/or, under the action of water vapor present in the atmosphere, may react with the latter and/or with one another, and/or may react chemically in another manner. There is also the danger that certain components present in the products, such as water, alcohol and other readily volatile substances, escape in the air by vaporization and/or evaporation from the products. It is known that preservatives and the like can be added to the products to inhibit undesired chemical changes of the stated type and possibly also to inhibit drying out. However, this is only partially successful. Moreover, preservatives may reduce the effectiveness of the active ingredients and/or have other undesired side effects.
It would therefore be advantageous in case of many products intended for skin care if they were stored in such a way that they do not come into contact with the air directly until they are used, i.e. during application to the skin. In the case of certain products containing a plurality of different active ingredients and auxiliaries, it would furthermore be advantageous, for avoiding undesired chemical reactions or other changes, to store two or more components of the relevant product separately and not mix the components until immediately before use, in the prescribed ratio.
2. Description of the prior art
There are already various dispensers for a pasty product, in particular toothpaste, having a store and a pump apparatus for pumping out the product. German Utility Model 8 518 670 discloses, for example a dispenser for dispensing a toothpaste having two components, i.e. having a main component and having an additional substance serving for the formation of colored stripes. The dispenser has a tubular container having an intermediate ceiling and a casing in which a piston is displaceable. The latter forms the lower limit of a main store containing the main component of the toothpaste. The container also serves as a support for the pump apparatus which has, above the intermediate ceiling, a pump element which is connected to said ceiling, is dome-shaped, consists of an elastically deformable membrane, is provided with a thick part providing rigidity in the central area of the dome and, together with the intermediate ceiling, defines a pump chamber. The intermediate ceiling is provided with an inlet valve which connects the main store to the pump chamber and has a rotatable valve flap. The pump chamber is connected via an approximately horizontal passage and an outlet valve, which has a rotatable valve flap, to an outlet which is arranged adjacent to the pump element at an edge position of the intermediate ceiling, is formed by a nozzle and has an approximately rectangular cross-section. Two stores, arc-shaped in outline, for the additional substance are present on both sides of the nozzle serving as an outlet. These two stores for additional substance are each connected, via an orifice present in the side walls of the outlet connection, to the outlet aperture defining the outlet connection. Each of the two stores for additional substance is limited at the bottom by an elastically deformable base which is provided with two non-return valves, each having a flap. One of these two non-return valves permits the passage of paste from the pump chamber into the relevant store for additional substance. The other non-return valve present in the base of each of the two stores for additional substance connects the relevant store for additional substance to the main store.
When the dispenser disclosed in German Utility Model 8 518 670 is filled, the additional substance is first introduced into the two stores for additional substance by means of a press, through the main store and the non-return valves connecting said store to the store for additional substance. The paste serving as the main component is then introduced into the main store from below, and the latter is closed with the piston. If a person uses the dispenser, he or she presses the dome-shaped pump element against the intermediate ceiling of the container, in opposition to the recovery force generated by the resilience of said pump element. When the pump element is pressed down, paste present in the pump chamber is pressed into the outlet and through the latter to the outside. At the same time, the non-return valves connecting the pump chamber to the stores for additional substance are also opened, so that paste is also forced from the pump chamber into the stores for additional substance. This paste in turn then forces additional substance stored in the latter into the outlet. If the person using the dispenser releases the pump element, the pump element arches upward owing to its resilience, paste being sucked from the main store into the pump chamber.
The dispenser disclosed in German Utility Model 8 518 670 has various disadvantages and would in particular be disadvantageous for dispensing a product intended for skin care. The outlet consisting of a nozzle in fact contains, after the dispenser has been used for the first time, a relatively large amount of the pasty product, which is exposed to the effect of air until the dispenser is next used. As already explained further above, contact with air may, however, have a very adverse effect on the products intended for skin care and furthermore may in certain circumstances cause blockage of the outlet as a result of the product drying out. Furthermore, the users of pasty skin care products are used to removing these with a finger from a jar-like or tub-like container, and pressing the product out of a nozzle is therefore undesirable and disadvantageous. Since, in the known dispenser, the pump chamber bordered at the top by the dome-shaped pump element, the passage connecting said chamber to the outlet, the outlet aperture defined by a nozzle and the stores for additional substance have relatively large volume, a relatively large amount of the product remains therein after the dispenser has been used for the last time, which is likewise disadvantageous in view of the high price of various skin care products. Since some of the paste pressed out of the pump chamber and serving as the main component of the product enters the stores for additional substance when the dispenser is operated, the components may mix in these stores which is also disadvantageous. The additional substance pressed out of the stores for additional substance into the outlet therefore presumably also contains, after the dispenser has been used a few times, some of the paste forming the main component. The mixing ratio of the two components may therefore change in an undesirable manner in the course of the period of use of the dispenser. Because the product components pumped out of the various stores follow a complicated path running around various corners, and because the piston is arranged below the paste present in the main store and must be pushed upward on emptying the main store, against its own weight and especially the weight of the paste present above it, a great deal of force is furthermore required for pumping out the product. In addition, the known dispenser is complicated and accordingly expensive.
A European Patent Application (Publication No. 0 363 307) of the applicant, published on Apr. 11, 1990, proposed dispensers with pump apparatuses in which the pump element defining the pump chamber on one side consists essentially completely of a membrane which is provided with an outlet aperture, and together with a rigid pin fastened to the wall part, forms the outlet valve. In the rest state, the membrane lies on the end face of the pin, part of said membrane surrounding the outlet aperture. If a person presses on the membrane with a finger, the product present in the pump chamber can cause the membrane to arch upward in the region of the pin, so that the outlet valve is opened and product can flow out through the outlet valve. In this dispenser, however, the membrane tends, when pressed, to arch upward depending on the pressure point, not only at the pin but also at other points remote from the pressure point, so that the volume of the pump chamber may not be reduced by the intended amount in certain circumstances and accordingly it is not the intended amount of product that is pressed out of the pump chamber and afterwards sucked into the pump chamber from the store when the membrane is released.